Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces
The energy transition across North America continues as the industry looks to integrate more zero-carbon emitting resources into the bulk power system. Part of this transition also involves the increasing penetration of renewable Distributed Energy Resources (DERs). As the penetration of DERs increases, the aggregate effects of DERs present both challenges and opportunities for planning, designing, and operating the bulk system (BPS).
The NERC System Planning Impacts from DER Working Group (SPIDERWG) has been analyzing the aggregate impacts that DERs can have on reliable operation of the BPS, and develops whitepapers, reliability guidelines, or standard authorization requests to address those impacts. Focus areas of the SPIDERWG are: displacement of generation providing various essential reliability services; balancing generation and demand and ramping requirements; adequate levels of voltage regulation and reactive power support; DER ride-through and trip settings; modelling and forecasting of DERs; and lack of observability or dispatchability of DERs.
The NERC Reliability and Security Technical Committee (RSTC) has just approved an updated reliability guideline that was developed by the SPIDERWG for IEEE 1547-2018. IEEE 1547-2018 specifies minimum technical interconnection and interoperability requirements for DERs connected to the distribution system. The updated guideline provides the relevant industry applications and a list of specific metrics on how to gauge industry application and effectiveness of the guideline. Entities in the MRO region should review the updated guideline and become familiar with IEEE 1547-2018 for what is applicable within each jurisdiction and what may have changed.
The primary purpose of the guideline is to be a reference for jurisdictions and registered entities in understanding the benefits of adopting IEEE 1547-2018. The guideline discusses IEEE 1547-2018 and bulk power reliability considerations that should be assessed during adoption, such as voltage and frequency mandatory trip settings, ride-through capability, DER enter service and return to service operations, DER controls configuration, and interoperability. The current version was updated from the 2003 version due to technology developments and industry experience with disturbance events.
Key perspectives for adopting jurisdictions and registered entities from the guideline include:
- Ride-through capability in general should be reviewed in the near term to mitigate the potential need to retrofit DERs as large-scale reconfiguration could be challenging and costly.
- Frequency tripping and ride-through settings should be coordinated to ensure that DER tripping is synchronized with wide-area under-frequency load shedding (UFLS) operation and interconnection-wide frequency response characteristics.
- Voltage ride-through requirements provide significantly improved capability and performance of DERs. The ability of DERs to ride-through transmission-level faults become a vital component of BPS stability as the penetration of DERs continues to increase. DER operation in the permissive operation and momentary cessation region needs to be coordinated to ensure appropriate performance from DERs during BPS fault events.
- Voltage trip requirements related to default settings of IEEE 1547-2018 are generally set to support BPS reliability and provide sufficient robustness to expected BPS grid disturbances.
- Enter service and return to service settings must be coordinated (e.g., voltage and frequency limits, return to service time, etc.). Unexpected or large changes in DER output may adversely impact restoration activities following wide-area disturbances. Adopting jurisdictions and registered entities need to understand expected load pickup behavior following outage conditions, including the response of DERs.
Key effectiveness metrics include:
- Aggregate DER performance during BPS disturbances through historic and current events in NERC’s Event Analysis process, through Lessons Learned, and other disturbance analysis.
- Number of states and provinces that have adopted the key clauses of 1547-2018 in this reliability guideline, number of states and provinces where utilities have adopted 1547-2018 settings but are waiting state or province adoption.
- Percentage of general reference to detailed reference by states and provinces that have adopted the key clauses of 1547-2018 from this reliability guideline.
Most manufacturers will complete certification to the IEEE standard in the March–August 2023 timeframe, and coordination activities for adoption and implementation of the standard is a key reliability topic for readers in the MRO region to consider on the road to grid transformation.
– Wayne Guttormson, Manager, Interconnections, System Planning and Asset Management, SaskPower
About the Author
Wayne Guttormson is the Manager – Interconnections, System Planning and Asset Management at SaskPower, in Saskatchewan, Canada. He has more than 25 years of transmission planning experience. Mr. Guttormson is a registered Professional Engineer in the province of Saskatchewan and has a Master of Science degree in Electrical Engineering from the University of Saskatchewan. His department is accountable for recommending system development plans for generation interconnections, open access transmission tariff service, inter-ties to the SaskPower system, and NERC reliability standards. Mr. Guttormson is also an at-large member of the NERC RSTC, and the RSTC sponsor of the SPIDERWG.